A common machine tool arrangement employed in the mass production of various articles wherein drilling, boring, reaming, grinding, and similar operations involve a rotating tool comprises a tool holding adapter removably attachable to a power driven spindle. Heretofore a complex latch mechanism has been required to hold the adapter and spindle in operative engagement with each other, often including radially extending lugs of the adapter interfitting and retained in place within recesses in the spindle by means of a trigger pin and compression spring mechanism. Such assemblies are not only complicated to use and expensive to manufacture, but are also subject to jamming when small chips get into the latch mechanism, as for example during extensive use. In such instances, removal of the tool holding adapter from the spindle is often difficult. Also if the latch mechanism involves radial lugs, small diameter assemblies are not feasible, and because of the large diameter of such assemblies, they cannot be used with closely spaced spindles in multiple spindle machines.
Important objects of the present invention are to provide an improved mechanism of comparatively simple and economical construction for releasably securing a tool holding adapter to a power driven spindle; wherein the adapter can be quickly attached in an operative position to the spindle, or quickly released, usually by finger manipulation; wherein the latch mechanism for attaching and releasing the adapter relative to the spindle is at all times shielded from particles of dirt, grindings, chips and the like; wherein a positive rotary drive mechanism between the spindle and adapter is completely independent of the latch mechanism; and wherein the outer diameter of the overall latch mechanism can if desired be no greater than the corresponding diameter of the spindle, thereby rendering the mechanism of the present invention especially suitable for use with multiple spindle machines or in small diameter applications.
Another object of the invention is to provide a tool holding adapter having a conically tapered shaft dimensioned to seat within a mating conically tapered opening extending coaxially into the forward end of a power driven spindle. A retention and rejection collar rotatable coaxially on a reduced diameter forward end of the spindle, but not movable axially relative to the spindle, is provided with an internally threaded portion in screw threaded engagement with an externally threaded portion of the adapter, whereby upon rotation of the collar in one direction or the other, the tapered shaft of the adapter is moved axially into or out of its seated position within the tapered spindle opening. A spline engagement between the spindle structure and adapter at the seated position provides a positive drive (independent of the latch mechanism) for rotating the adapter upon rotation of the spindle. Also the threaded connection between the collar and adapter is preferably arranged so that rotation of the collar in the direction for moving the adapter to the seated position is opposite the rotational direction of the spindle during operation of the tool.
Other and more specific objects are to provide the threaded connection between the collar and adapter with an acme type thread dimensioned to move the adapter from its seated position to a position out of engagement with the collar upon approximately a single full turn of the collar; to provide effective means for retaining the collar against axial movement along the spindle while enabling freedom of rotation comprising a resilient C-type ring having inner and outer peripheral portions confined respectively within confronting coaxial annular grooves in the outer periphery of the reduced diameter portion of the spindle and an overlying inner cylindrical surface of the collar; and to provide the adapter with an extension rearwardly of its tapered shaft in splined engagement with the sidewalls of a coaxial recess of the spindle that also extends rearwardly from the conically tapered opening of the spindle, whereby an unbroken outer cylindrical surface of the spindle at a location adjacent to and rearwardly of the rotatable collar may be provided and used for a spindle bearing support at said location.
Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.